1. Technical Field
The present invention relates to an evaluation system for determination of cardiovascular function parameters and, more particularly, to such an evaluation system for use in clinical diagnosis.
2. Description of Related Art
Cardiac function parameters such as the ejection fraction and the ventricular volume are typically evaluated by nuclear medicine diagnosis, and this has been the case for quite a long time. Basically, the evaluation process involves injecting a radioactive tracer (e.g., TC-99m) into a patient's or a test subject's body, allowing the tracer to be distributed evenly in the patient's or the test subject's blood. Then, by detecting the distribution, and variation thereof, of the radioactive tracer in the patient's or the test subject's heart with a nuclear medicine imaging apparatus, the ejection fraction and the ventricular volume can be evaluated. As radioactive tracers are harmful to the human body, it is highly desirable that cardiac function parameters can be directly derived from images obtained by non-invasive photographic techniques that feature non-ionizing radiation, with a view to reducing patients' and test subjects' exposure to radiation.
U.S. Pat. No. 7,603,154 discloses a method for estimating the left ventricular (LV) volume during a cardiac cycle using endocardial contours in three-dimensional (3D) cardiac images taken at end diastole, wherein the contours can be manually specified or semi-automatically derived. Based on the contours and on the pixel intensity of all the images, the LV volume is estimated according to intensity variations within the area enclosed by the contours. The ventricular volume and the ejection fraction can be derived in this way because the intensity variations are related to the change in size of the ventricle.
While U.S. Pat. No. 7,603,154 discloses a method whereby function parameters related to the ventricular volume can be derived from 3D cardiac images, the calculation of other cardiac function parameters (e.g., a ventricular wall displacement parameter) remains unsolved. Nowadays, methods for obtaining cardiovascular images by non-ionizing radiation techniques and deriving cardiac function parameters other than those related to the ventricular volume from the cardiovascular images in real time are still unavailable. Hence, there is a need to develop a method by which cardiovascular function parameters other than those related to the ventricular volume can be evaluated using cardiovascular ultrasound images.